It’s estimated that a washing machine contributes about 22% of the liquid input to your septic tank. But, while it would seem like a good idea to get rid of nearly a quarter of the flow into the tank to help the system last longer, sending your washing machine drain cycle into a puddle in the yard is a health hazard. 

    Once you consider that what is euphemistically called “skid marks” in your family’s underwear will be washed out onto the ground, you can understand why this is not recommended and called out as a defect on a home inspection report. All “black water” from toilets, urinals, and kitchen drains, along “gray water” from washing machines, sinks and showers, should stay connected to the septic system. Here’s the citation from the Florida Residential Building Code:

    Gray water is allowed, however, to be used for flushing toilets or urinals where there is an approved gray water system is installed. The requirements for approval of a gray water recycling system are extensive and probably not worth it for most homeowners. 

    See our blog post What are the building code requirements for gray water reuse in Florida? and What can I add to my septic tank to help it work better? to learn more. 

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  To learn more about septic tank systems, see these other blog posts:

• Why do septic tank contractors want you to get rid of your kitchen disposal?

• How can I tell if a house is connected to a septic tank system or sewer?

• How can I locate my septic tank? 

• Does a septic tank have to be re-certified if a house has been vacant for a while?

• What is a grinder pump? 

• How often should I pump out the septic tank?

• Should I call a plumber or septic tank contractor when my septic tank backs up into the house? 

• Do I have to get a larger septic tank when I build a home addition?

• Where is the septic tank? Are you going to inspect it? 

• Can a house have more than one septic tank?

• What is the difference between gray water and black water in the plumbing code? 

    Visit our PLUMBING and SEPTIC TANK SYSTEMS pages for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.